An indicator based approach for assessing household’s perceptions of landslide risk in Murree hills of Pakistan     

Qasim  Said  Qasim  Muhammad 《Natural Hazards》2020,103(2):2171-2182

Natural Hazards - The Murree region in Pakistan is frequently affected by landslides and causes damages to lands, houses, life lines and even loss of livestock and human life. We have attempted in...  相似文献   

On the Application of the Novel Thin Spray-on Liner (TSL): A Progress Report in Mining Operations     

Kolapo  Peter  Onifade  Moshood  Said  Khadija Omar  Amwaama  Martha  Aladejare  Adeyemi Emman  Lawal  Abiodun Ismail  Akinseye  Praise Oluwatomisin 《Geotechnical and Geological Engineering》2021,39(8):5445-5477

Stability is the main problem in underground excavations that can result in rock-related accidents or closure of mines. This is often controlled by the geological condition of the rockmass and the in situ stress field where excavation is being carried out. Over the years, conventional support systems such as bolts, shotcrete and mesh have been the standard support systems used in difficult ground conditions to maintain stability of underground openings. The novel Thin Spray Liner (TSL) is a technology with an improvement in terms of support capabilities for difficult geological conditions. This technology is predicted to replace conventional support systems, as it offers a significant yielding capacity that is better than that of the traditional techniques of controlling strata. The performance of the TSL lies between that of shotcrete and wire mesh. The TSL has numerous advantages regarding rock reinforcement such as rapid curing period, fast application, high tensile strength, high adhesion properties that prevent movement of rock keyblocks, improved cycle times, reduction in material-handling compared to shotcrete, and a significant ability to penetrate joints. These advantages increase the allowance for mechanisation and improvement of safety in excavations. Despite various benefits of TSLs, there are shortcomings which make end-users to be sceptical about the technology. This study provides a detailed review of the mechanism, properties, composition and types, as well as the general and mining applications of TSLs. It also describes the challenges faced by the mining industry and other end-users in accepting the technology as a solution for stability issues in underground openings. In addition, some insightful suggestions are made as recommendations for future work on the development of suitable, effective and efficient thin surface rock support technology within limitations/constraints.

  相似文献   

The Djidjelli (Algeria) earthquakes of 21 and 22 August 1856 (I<Subscript>0</Subscript> VIII,IX) and related tsunami effects Revisited     

Assia Harbi  Mustapha Meghraoui  Said Maouche 《Journal of Seismology》2011,15(1):105-129

New historical data from primary sources, allow us to revisit the Djidjelli earthquakes of 21 and 22 August 1856 (I₀ VIII, IX respectively). These two large seismic events are among the most significant events that have affected the North African coast. They have caused extensive damage and generated a tsunami that propagated at several harbours of the western Mediterranean Sea. The effects of each earthquake are analysed from all documentary source materials, emphasising the confrontation of observations and data for an accurate reconstruction of the macroseismic field of both events. The method used provides a more precise way to determine the characteristics of the Djidjelli earthquakes.  相似文献   

Spatiotemporal drought variability in northwestern Africa over the last nine centuries   总被引：3，自引：1，他引：2  

Ramzi Touchan  Kevin J. Anchukaitis  David M. Meko  Mohamed Sabir  Said Attalah  Ali Aloui 《Climate Dynamics》2011,37(1-2):237-252

Changes in precipitation patterns and the frequency and duration of drought are likely to be the feature of anthropogenic climate change that will have the most direct and most immediate consequences for human populations. The latest generation of state-of-the-art climate models project future widespread drying in the subtropics. Here, we reconstruct spatially-complete gridded Palmer drought severity index values back to A.D. 1179 over Morocco, Algeria, and Tunisia. The reconstructions provide long-term context for northwest African hydroclimatology, revealing large-scale regional droughts prior to the sixteenth century, as well as more heterogeneous patterns in sixteenth, eighteenth, and twentieth century. Over the most recent decades a shift toward dry conditions over the region is observed, which is consistent with general circulation model projections of greenhouse gas forced enhanced regional subtropical drought.  相似文献   

Patterns of genetic and morphometric diversity in the marbled crab (Pachygrapsus marmoratus, Brachyura, Grapsidae) populations across the Tunisian coast   总被引：1，自引：1，他引：0  

Temim Deli  Hiba Bahles  Khaled Sai  Noureddine Chatti 《海洋学报(英文版)》2015,34(6):49-58

The present study reports on population structure analysis of the marbled crabPachygrapsus marmoratus (Fabricius, 1787) from the Tunisian coast, an appropriate location to study biogeographical process...  相似文献   

Response-based method for determining the extreme behaviour of floating offshore platforms     

Said Mazaheri  Martine J. Downie 《Ocean Engineering》2005,32(3-4):363-393

The accurate prediction of extreme excursion and mooring force of floating offshore structures due to multi-variete environmental conditions which requires the joint probability analysis of environmental conditions for the worst case situation is still impractical as the processing of large amount of met-ocean data is required. On the other hand, the simplified multiple design criteria (e.g. the N-year wave with associated winds and currents) recommended by API known as traditional method does lead neither to the N-year platform response nor to the N-year mooring force. Therefore, in order to reduce the level of conservatism as well as uncertainties involved in the traditional method the response-based method can be used as a reliable alternative approach. In this paper this method is described. In order to perform the calculations faster using large databases of sea states, Artificial Neural Networks (ANN) is designed and employed. In the paper the response-based method is applied to a 200,000 tdw FPSO and the results are discussed.  相似文献   

A quantitative analysis on the Egyptian Mediterranean waters     

M. A. Sai  F. M. Eid 《海洋学报(英文版)》1994,13(2):203-212

ＡｑｕａｎｔｉｔａｔｉｖｅａｎａｌｙｓｉｓｏｎｔｈｅＥｇｙｐｔｉａｎＭｅｄｉｔｅｒｒａｎｅａｎｗａｔｅｒｓ￥Ｍ．Ａ．ＳａｉｄａｎｄＦ．Ｍ．Ｅｉｄ（ＲｅｃｅｉｖｅｄＳｅｐｔｅｍｂｅｒ２１，１９９３１ａｃｃｆｅｐｔｅｄＪａｎｕａｒｙ１５，１９９４）Ａｂｓ...  相似文献   

Iron oxide copper-gold (IOCG) mineralization at the Imiter inlier,Eastern Anti-Atlas,Morocco     

Bouchra Baidada  Abdelkhalek Alansari  Basem Zoheir  Said Ilmen  Abderrahmane Soulaimani  Moha Ikenne 《Chemie der Erde / Geochemistry》2018,78(4):462-478

The Imiter inlier at the eastern Anti-Atlas chain (Morocco) hosts a world-class epithermal Ag-Hg deposit, and several occurrences of sulfide-magnetite mineralization. These occurrences are confined to transcurrent faults that cut mildly to highly potassic I- and S-type granite intrusions (e.g., Igoudrane, Bou Teglimt, Taouzzakt and Bou Fliou).In this contribution, we present new field, petrographic and microanalytical data of the Bou Fliou sulfide-magnetite mineralization in the northwestern part of the Bou Teglimt granodiorite intrusion (567?±?6Ma). Field and microscopic investigations reveal pervasive silicification and potassic alteration associated with iron oxides-rich (>10?vol %) veins, stockworks, and breccias along NE-SW faults. The ore minerals are mainly magnetite, hematite, chalcopyrite, pyrite, sphalerite, Ag-galena, cobaltite, and less abundant Bi-sulfosalts (i.e., cosalite, galenobistmuthite, and llilanite-gustavite). The low-titanium iron oxides (magnetite and hematite), widespread iron-rich breccia, association with crustal scale fault zone, pervasive alteration, and overprinting mineral assemblages suggest a shallow level IOCG-style mineralization. High-order splays of the major fault zone could have provided effective traps for magmatic and basinal Cu and Zn-Pb hydrothermal fluids. The ～550 Ma intrusive phases in the region could have contributed by fluid, elements or heat in a local effective blumbing. The mineralogical and ore textural criteria reflecting ore formation at a realtively shallow crustal environment, but a fluid inclusion study is needed to characterize the ore fluids and mechanism of ore deposition.  相似文献   

Effect of the combination of lime and natural pozzolana on the compaction and strength of soft clayey soils: a preliminary study   总被引：1，自引：0，他引：1  

Khelifa Harichane  Mohamed Ghrici  Said Kenai 《Environmental Earth Sciences》2012,66(8):2197-2205

Soft soil stabilization has been practised for quite some time by mixing additives, such as cement, lime and fly ash to the soil to increase its strength. However, there is a lack of investigations on the use of natural pozzolana alone or combined with lime for ground improvement applications. An experimental programme was undertaken to study the effect of using lime, natural pozzolana or a combination of both on the geotechnical characteristics of soft soils. Lime or natural pozzolana was added to soft soils at ranges of 0?C10% and 0?C20%, respectively. In addition, combinations of lime?Cnatural pozzolana were added to soft soils at the same ranges. Test specimens were subjected to compaction tests, shear tests and unconfined compression tests. Specimens were cured for 1, 7, 28 and 90?days, after which they were tested for unconfined compression tests. Based on the favourable results obtained, it can be concluded that the soft soils can be successfully stabilized by the combined action of lime and natural pozzolana. Since natural pozzolana is much cheaper than lime, the addition of natural pozzolana in lime?Csoil mix may particularly become attractive and can result in cost reduction of construction.  相似文献   

Monitoring of wastewater percolation in unsaturated sandy soil using geoelectrical measurements at Gabal el Asfar farm,northeast Cairo,Egypt   总被引：5，自引：5，他引：0  

Khaled M. Said Gemail 《Environmental Earth Sciences》2012,66(3):749-761

The use of wastewater for irrigation in sandy soil increases the pollution risk of the soil and may infiltrate to the shallow groundwater aquifer. In such environment, some important parameters need to be obtained for monitoring the wastewater in the unsaturated zone over the aquifer. These parameters include clay content, heterogeneities of the upper soils, depth to the aquifer and the variations of groundwater quality. In the present work, the efficiency of DC resistivity method in forms of 1-D and 2-D measurements was studied for wastewater monitoring in the Gabal el Asfar farm, northeast of Cairo, Egypt. Forty-one Schlumberger soundings (VES) were performed then followed by three pole-dipole 2-D profiles along some considered regions within the area. The resistivity measurements were integrated with the boreholes, hydrogeological and hydrochemical (surface and groundwater samples) information to draw a clear picture for the subsurface conditions. The obtained results were presented as cross sections and 3-D visualization to trace the clay intercalations within the unsaturated zone. In addition, a vulnerability map was created using the obtained results from 1-D Schlumberger survey and confirmed with the 2-D resistivity profiling. The obtained results have shown that the 2-D resistivity imaging technique is a powerful tool for mapping the small-scale variability within the unsaturated zone and the wastewater infiltration. However, limitations of resistivity techniques were observed in the area with limited resistivity contrast such as thin clay layers with brackish water background. Under that condition, the measured pattern of resistivity distributions depends on the applied electrode array, electrode spacing and using the available geological information during the inversion process.  相似文献